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Biomedical subjects

T Oda

Publications and source records attributed to T Oda.

At least 433 records · Page 24Linked to original sources
PubMed1991

Three-dimensional translational movements of the upper cervical spine.

In 10 fresh cadaveric specimens of occiput (C0) to C3, six pure moments (maximum 1.5 Nm) were applied and the resulting physiological motions were studied. We determined the quantitative three-dimensional relative translations of two specific midsagittal points on C0 and C1: the anterior (point A) and posterior (point B) margins of the foramen magnum of C0, and the posteroinferior margin of anterior arch (point C) and the anteroinferior margin of posterior arch (point D) of C1. In flexion/extension, translational movements of these four points were mainly in the sagittal plane. In axial torque and lateral bending moment, both points on C0 shifted laterally, to the same side of axial torque and to the opposite side of lateral bending. The pattern of the translation of C1 in left axial torque was similar to that in the right lateral bending moment, although the magnitude was larger in the former. In these situations, point C moved to the left, and point D moved to the right and anterior. The vertical translation had two phases: superior translational phase, followed by inferior translational phase. We presented the quantitative translations but, because of large standard deviations between the specimens, it was difficult to define translational thresholds for instability.

Adult↗
PubMed1991

Experimental study of atlas injuries. I. Biomechanical analysis of their mechanisms and fracture patterns.

Understanding injury mechanisms is important for the prevention, diagnosis, and treatment of spinal injuries. Using 10 fresh cadaveric human spine specimens of occiput to C3, clinically similar injuries of the atlas (C1) were produced with high-speed (4.4 m/sec) axial compression. The traumatic event was biomechanically monitored. The resulting injuries were studied with radiography, computed tomography, and a multidirectional instability test. The average compressive failure force was 3,050 N for specimens impacted in neutral posture (n = 437) and 2,100 N for those in extended posture (n = 282). Corresponding values for the impulse were 34.9 Nsec (n = 8.3) and 17.6 Nsec (n = 1.8). Average instability for both groups, as measured by the neutral zone and range of motion, increased by 90% and 44%, respectively, in flexion-extension and 20% in lateral bending, but not in axial rotation. These findings confirm the clinical observations.

Biomechanical Phenomena↗
PubMed1991

Experimental study of atlas injuries. II. Relevance to clinical diagnosis and treatment.

Atlas injuries were produced in vitro and evaluated by radiographic examinations and anatomic studies from a clinical viewpoint. Ten cadaveric human upper cervical spine specimens were subjected to a high-speed axial impact. Injuries to the atlas consisted of six bursting fractures, two ruptures of the transverse ligament, one four-part fracture without a prominent bursting, and one posterior arch fracture. The major soft tissue injury involved the transverse ligament. There were five bony avulsions and three midsubstance tears. In this study, computed tomographic examinations clearly demonstrated the sites of fracture and bony avulsions of the transverse ligament. The best diagnostic tool for function of the transverse ligament was determined to be the atlantodental interval on flexion radiographs. Axial traction force reduced a bursting fracture of the atlas ring. The in vitro atlas injury model gives useful information for clinical diagnosis and treatment.

Biomechanical Phenomena↗
PubMed1991

Transections of the C1-C2 joint capsular ligaments in the cadaveric spine.

The purpose of this study was to examine the mechanical function of the C1-C2 capsular ligaments. Physiologic torques of up to 1.5 Nm were applied to human fresh cadaveric specimens (C0-C1-C2-C3) in three dimensions, and the three-dimensional motion of C1 relative to C2 was recorded. Two groups of cadaveric specimens were used to study the effect of two different sequential ligamentous transections. In the first group (n = 4), the transection of the left capsular ligament was followed by transection of the right capsular ligament. In the second group (n = 10), the transection of the left capsular ligament was preceded by transection of the left and right alar and transverse ligaments. The greatest changes in motion occurred in axial rotation to the side opposite the transection. In the first group, left capsular transections resulted in a significant increase in axial rotation range of motion to the right of 1 degree. After the right capsular ligament was transected, there was a further significant increase of 1.8 degrees to the left and 1.0 degree to the right. Lateral bending to the left also increased significantly by 1.5 degrees after both ligaments were cut. In the second group, with the nonfunctional alar and transverse ligaments, transection of the left capsular ligament resulted in greater increases in range of motion: 3.3 degrees to the right and 1.3 degrees to the left. Lateral bending to the right also increased significantly by 4.2 degrees.

Cadaver↗
PubMed1991

Synaptosomal protein kinase C subspecies: A. Dynamic changes in the hippocampus and cerebellar cortex concomitant with synaptogenesis.

The expression of protein kinase C (PKC) subspecies in synaptosomes prepared from a number of adult brain regions was compared. Cerebral cortical and thalamic/striatal synaptosomes were found to express three peaks of enzyme activity upon hydroxyapatite chromatography, corresponding to the type I(gamma), type II(beta), and type III(alpha) subspecies. Synaptosomes prepared from either the hippocampus or the cerebellar cortex, however, contained only two major peaks, corresponding to the alpha- and beta-subspecies, with barely detectable levels of the gamma-subspecies, even though these tissue areas were enriched in the latter enzyme. When the ontogenic pattern of hippocampal synaptosomal PKC subspecies was examined, it was found that at postnatal day 7, significant quantities of the gamma-subspecies were present and that this subspecies reached its peak levels at around postnatal day 14, before steadily declining to its adult level. Similar changes were observed also for the gamma-subspecies in cerebellar cortex synaptosomes. The dynamic changes in the synaptosomal PKC subspecies take place at a critical period in the development of the rat brain, concomitant with an active period of synaptogenesis, suggesting that it may play a role in synaptogenesis.

Aging↗
PubMed1991

Synaptosomal protein kinase C subspecies: B. Down-regulation promoted by phorbol ester and its effect on evoked norepinephrine release.

The effect of phorbol esters was investigated on the down-regulation of protein kinase C (PKC) and on the release of [3H]norepinephrine (NE) in synaptosomes from the rat cerebrum. Treatment with 12-O-tetradecanoylphorbol 13-acetate (TPA) promoted the translocation of PKC activity in a P2 fraction from the cytosol to the membrane fraction and then its down-regulation, in a dose-dependent manner. TPA induced a rapid down-regulation of the type II(beta) and type III(alpha) subspecies, but did not change the activity of the type I(gamma) subspecies in the cytosolic fraction for at least 15 min. The gamma-subspecies was subsequently decreased at a slower rate. In the synaptosomes thus having only the gamma-subspecies, a subsequent dose of TPA could not enhance K(+)-evoked NE release, although, in the original synaptosomes, TPA was able to enhance K(+)-evoked NE release. Pretreatment with TPA did not alter the K(+)-evoked NE release itself. TPA was also found to enhance the K(+)-evoked NE release from synaptosomes prepared from both hippocampus, which express the gamma-subspecies of PKC at a negligible level, and cerebral cortex, which have a significant level of the gamma-subspecies, to the same degree. These results suggest that the gamma-subspecies of PKC does not participate in the TPA-enhanced K(+)-evoked NE release from synaptosomes.

Animals↗
PubMed1991

Skeletal muscle powered ventricle: comparison of double-layered small ventricle and single-layered large ventricle.

Canine left latissimus dorsi (LD) muscles were used to construct two kinds of skeletal muscle powered ventricles (SMPV): a double layered small size (10-17 mL) SMPV (A), and a single-layered large size (40-70 mL) SMPV (B). The same muscle was used sequentially for the construction of both SMPV. A mock circulation system was used for testing. This allowed for change of the preload (10-60 mmHg) and afterload (40-160 mmHg) independently. The peak developed pressure (PDP) and stroke volume (SV) were measured, and the stroke work (SW) was analyzed on line by a computer. The isovolumic PDP was 93.3 +/- 11.8 mmHg at 10 mmHg preload, and 157.7 +/- 20.2 mmHg at 60 mmHg for A, and 37.8 +/- 5.5 mHg and 107.8 +/- 8.5 mmHg for B. The SV and SW at 50 mmHg preload and 80 mmHg afterload were 18.30 +/- 1.25 mL and 1.06 +/- 0.10 x 10(6) erg for A, and 34.18 +/- 2.36 mL and 2.51 +/- 0.28 x 10(6) erg for B. The SV and SW at 20 mmHg preload and 160 mmHg afterload were 2.65 +/- 0.31 mL and 0.27 +/- 0.05 x 10(6) erg for A, and 1.03 +/- 0.23 mL and 0.04 +/- 0.01 x 10(6) erg for (B). The SW generated by the large single-layered SMPV is similar to that reported for the canine left ventricle but requires a high preload. The large single-layered SMPV showed a higher dependence on pre- and afterload changes than the double layered small SMPV, which generates a higher pressure even at low preloads.

Animals↗
PubMed1991

Possible contribution of prolactin in the process of ovulation and oocyte maturation.

The present study was undertaken to evaluate the effects of PRL in the process of ovulation and oocyte maturation. In the first experiment, using an in vitro perfused rabbit ovary model, the addition of PRL to the perfusate inhibited hCG-induced ovulation in a dose-related fashion, without any reduction in progesterone synthesis. In a subsequent experiment, PRL directly inhibited both the degeneration and decomposition of surface epithelial cells and the disruption of connective tissue at the apex of the follicle wall. Furthermore, PRL inhibited hCG-stimulated plasminogen activator (PA) activity in mature follicles in a dose-related fashion. In the final experiment, we demonstrated conditions in which rabbit oocytes matured in vitro acquire competence for early embryonic development. PRL, as well as gonadotropins and estradiol, was an important constituent in the process of oocyte maturation, promoting embryonic development. These results suggest that the preovulatory environment of PRL within the follicle may influence the process of ovulation and oocyte maturation.

Animals↗
PubMed1991

Effects of prolactin on fertilization and cleavage of human oocytes.

The effects of PRL on fertilization and cleavage of human oocytes and subsequent pregnancy were studied. Forty-five patients (47 cycles) with euprolactinemic normal menstrual cycles undergoing in vitro fertilization (IVF) for the treatment of tubal infertility were selected for this study. The patients were divided into three groups dependent upon their mean serum PRL concentrations for the 3 days prior to oocyte retrieval; hypoprolactinemic (less than 10 micrograms/l), euprolactinemic (10-30 micrograms/l) and hyperprolactinemic cycles (greater than or equal to 30 micrograms/l). Multiple follicular development was induced with hMG, and 10 patients were randomized to receive bromocriptine beginning with the previous menstrual cycle. In the hypoprolactinemic cycle group, the fertilization rate was significantly lower than in the hyperprolactinemic cycle group, and the cleavage rate was significantly lower than in the other groups. The fertilization rates and the cleavage rates in the hyperprolactinemic cycle group were higher than those in the euprolactinemic cycle group; however, these differences were not statistically significant. While the pregnancy rates in the euprolactinemic cycle group were higher than in the other two groups, the numbers were too small for meaningful statistical comparison. The present study demonstrates that below normal concentrations of PRL have deleterious effects on IVF outcome. These data suggest that PRL may play a beneficial stimulatory role in oocyte maturation and the acquisition of developmental capacity.

Adult↗
PubMed1991

Inhibition of transcription by mammalian ribonucleic acid polymerase II: effects of diethylstilbestrol and its analogues.

We examined the effects of diethylstilbestrol (1), Z,Z-dienestrol (2), E,E-dienestrol (3), indenestrol A (4), indenestrol B (5) and estradiol (6) on the activity of in vitro accurate transcription from adenovirus 2 major late promoter by mammalian ribonucleic acid (RNA) polymerase II using partially purified transcription factors from HeLa cell nuclear extract as well as on RNA polymerase II activity assayed for random incorporation of ribonucleotides. 1, 2, and 3 inhibited both activities, whereas 4 and 5 were inhibitory only in the transcription activity at concentrations higher than 10 micrograms/ml. However 6 had no effects on both activities.

Adenoviridae↗
PubMed1991

An autopsy case of spinal arteriovenous malformation (Foix-Alajouanine syndrome).

An autopsy case of spinal arteriovenous malformation (AVM) was reported. The patient was a 75-year-old male and his initial neurologic symptoms were paraplegia, paresthesia below the umbilical level and urination difficulty. Subsequently night delirium and parkinsonism also appeared. The clinical and pathological findings in this case are identical with those in the spinal AVM except for Parkinson's disease. In addition, the lateral funiculus of the spinal cord in the middle thoracic segment showed pallor: Under light microscopy, the funiculus was spongiform, with a thinner wall of the myelin sheath, enlargement of the axon and the perivascular infiltration of phagocytes without plasma exudation. The changes in the lateral funiculus seemed to indicate early congestive changes.

Aged↗
PubMed1991

A sequential immunosuppressive treatment with mizoribin (Bredinin) plus cyclosporin A on the subrenal capsule assay.

To minimize immunological interferences on the subrenal capsule (SRC) assay, a new immunosuppressor, mizoribin (MZB: Bredinin) alone or combined with cyclosporin A (ScA) was evaluated by an experimental SRC assay system using a rat ovarian cancer tissue. Daily applications of MZB (200 mg/kg) for 7 days following the xenograft of cancer tissue were insufficient to suppress immunological reactions of the recipient mice, and all the grafted cancer tissues were rejected. Although CsA monotreatment (60 mg/kg of CsA given daily for 7 days) successfully suppressed the host immune reaction, enhanced toxicities of CsA in combination with anticancer agents caused high lethal rate of host mice during the experimental chemotherapy. Sequential use of CsA on day 0 to day 2 followed by MZB on day 3, 5 and 7 brought the most favorable results with minimal host reactions and toxicities. An anticancer screening test using the modified SRCA accurately reflected the results of experimental chemotherapy against the rat ovarian cancer. The immunosuppressive treatment which minimizes immunological interferences with SRC assay chemoscreening test.

Animals↗
PubMed1991

Minimal deviation adenocarcinoma (adenoma malignum) of the uterine cervix associated with mucinous ovarian carcinoma.

A case of minimal deviation adenocarcinoma (MDA: adenoma malignum) of the uterine cervix associated with ovarian mucinous carcinoma is documented. Diagnosis was possible only retrospectively after surgery by histological examinations including immunohistochemistry. Three courses of chemotherapy, consisting of cisplatin, doxorubicin and ifosfamide, could eradicate the residual diseases of ovarian cancer from the peritoneal cavity, but was insufficiently effective against lymph node metastases of the cervical MDA. Subsequently, the disease flared-up retroperitoneally during the sixth course of treatment course, suggesting chemoresistance developed, and further chemotherapy using different regimens were not effective. Therapeutic intractability of MDA as well as the diagnostic difficulty was again emphasized.

Adenocarcinoma↗
PubMed1991

Prediction of contractile reversibility in impaired left ventricular wall motion following coronary artery bypass grafting.

Interventional left vertriculograms (LVGs) using postextrasystolic potentiation (PESP), nitroglycerin (TNG) and a combination of both were analyzed in order to decide the degree of efficacy of each intervention as a predictor of reversibility in impaired left ventricular segments. Segmental wall motion (SWM) in less severely impaired segments increased to the normal range and SWM in severely impaired segments increased but remained in the abnormal range after CABG. The effects of both PESP and TNG on SWM in impaired segments correlated (r = 0.78 and 0.78) with that of CABG. The increase in SWM due to TNG + PESP was significantly (p < 0.01) greater than that due to either PESP or TNG alone or that of CABG. Either PESP or TNG was clinically reliable for prediction of contractile reversibility in the segments with impaired wall motion prior to CABG. Including the global left ventricular function, PESP reflected the efficacy of CABG more sufficiently than TNG. TNG + PESP provoked more contractile reserve and exaggerated the results of CABG, but may predict reversibility in severely reduced wall motion.

Adult↗
PubMed1991

[The effect of abnormal lipid metabolism to glomerular injury].

To clarify the effect of abnormal lipid metabolism and lipid deposition in glomerular injuries, we conducted clinical and pathological examination of various glomerulonephritis. There was no relationship between serum TC, TG or apo B and renal deposition of apo B or TG in glomerulonephritis. Apo B staining was intense for MCNS but was very weak for FGS. The staining was more intense in higher grade of glomerular injury in IgAN. Apo B demonstrated a specific pattern for MN, MPGN and lupus nephritis. These data suggest that apo B deposition reflects disturbance of glomerular permselectivity of macromolecules including abnormal influx, transport and endocytosis of macromolecules.

Apolipoproteins↗
PubMed1991

[Prolonged traumatic coma caused by diffuse axonal lesions].

A 22-year old male patient was admitted for deep coma probably of traumatic origin. There was neither fracture of the skull nor expansive intracranial lesion. The patient survived for 6 years and 8 months without any change in consciousness. Post-mortem neuropathological examination showed lesions which predominated in the white matter and had features that were compatible with diffuse axonal injury. The mechanism responsible for these lesions seems to be stretching and shearing of axones at the moment of impact. The exceptionally long duration of survival probably accounts for the severity of the lesions observed.

Adult↗
PubMed1991

[Treatment of mediastinal infection after coronary artery bypass surgery by transposition of the greater omentum].

From January, 1986 to May, 1990 twenty one adult patients (men 16, women 5, age 64 +/- 7 years old) underwent transposition of the greater omentum to control mediastinal infection after coronary artery bypass surgery. Upon diagnosing mediastinitis, the mediastinum was drained open and irrigated with 0.5% povidone iodine-saline solution until the omental transposition. The interval between the diagnosis of mediastinitis and the omental transposition ranged from 0 to 171 (mean 19) days. Three quarters of the patients had the omentum transposed within 14 days. In nineteen of 21 patients (90%) the mediastinitis was effectively controlled. In the remaining two patients the infection could not be controlled and proceeded to succumb from multiple organ failure. There was no complication related to the omental transposition in itself. We conclude that transposition of the greater omentum is a safe and effective method for treating mediastinal infection after coronary artery bypass surgery.

Aged↗